Isolated switching power supply apparatus

Abstract

An isolated switching power supply apparatus includes a transformer, a primary-side circuit that includes at least a switching element and supplies input power from an input terminal to a primary winding by controlling on/off of the switching element, and a secondary-side circuit that is electrically isolated from the primary-side circuit and that outputs output power resulting from power conversion performed by the transformer from a secondary winding to an output terminal. The apparatus includes a first circuit board to which the primary winding is connected and that includes the primary-side circuit and the input terminal, and a second circuit board to which the secondary winding is connected and that includes the secondary-side circuit and the output terminal. The first and second circuit boards are stacked in a multilayer manner. The primary and secondary windings are arranged around a core that extends through the first and second circuit boards.

1 . (canceled) 
     
     
         2 . An isolated switching power supply apparatus comprising:
 a transformer that includes a primary winding, a secondary winding, and a core;   a primary-side circuit that includes at least a switching element and supplies input power from an input terminal to the primary winding by controlling on/off of the switching element;   a secondary-side circuit that is electrically isolated from the primary-side circuit and outputs, from the secondary winding to an output terminal, output power resulting from power conversion performed by the transformer;   a first circuit board to which the primary winding is connected and that includes the primary-side circuit and the input terminal; and   a second circuit board to which the secondary winding is connected and that includes the secondary-side circuit and the output terminal; wherein   the first circuit board and the second circuit board are stacked in a multilayer manner, and the core extends through the first circuit board and the second circuit board such that both the primary winding and the secondary winding are arranged around the core.   
     
     
         3 . The isolated switching power supply apparatus according to  claim 2 , wherein the first and second circuit boards are arranged such that a distance between the primary winding and the secondary winding is changed by changing a distance between the first circuit board and the second circuit board so as to change an amount of leakage inductance occurring in the transformer, and
 the leakage inductance occurring in the transformer is used as an inductance of an inductor connected in series with the primary winding or the secondary winding.   
     
     
         4 . The isolated switching power supply apparatus according to  claim 2 , further comprising a spacer that defines a distance between the first circuit board and the second circuit board. 
     
     
         5 . The isolated switching power supply apparatus according to  claim 2 , wherein the primary winding includes a coil pattern on the first circuit board and the secondary winding includes a coil pattern on the second circuit board. 
     
     
         6 . The isolated switching power supply apparatus according to  claim 2 , wherein
 components of the primary-side circuit are arranged on a surface of the first circuit board that is a farthest surface from a surface facing the second circuit board; and   components of the secondary-side circuit are arranged on a surface of the second circuit board that is a farthest surface from the surface facing the first circuit board.   
     
     
         7 . The isolated switching power supply apparatus according to  claim 2 , wherein the primary winding circuit includes at least two switching elements and at least two capacitors. 
     
     
         8 . The isolated switching power supply apparatus according to  claim 2 , wherein the secondary winding circuit includes at least two rectifier diodes and a smoothing capacitor arranged to define a rectifying-and-smoothing circuit. 
     
     
         9 . The isolated switching power supply apparatus according to  claim 4 , wherein the spacer includes a spacer portion and a shaft portion that extends from both ends of the spacer portion. 
     
     
         10 . The isolated switching power supply apparatus according to  claim 4 , wherein the spacer is made of conductive material. 
     
     
         11 . The isolated switching power supply apparatus according to  claim 4 , wherein the spacer defines the input terminal and is electrically isolated from the second circuit board. 
     
     
         12 . The isolated switching power supply apparatus according to  claim 4 , wherein the spacer defines the output terminal and is electrically isolated from the first circuit board. 
     
     
         13 . The isolated switching power supply apparatus according to  claim 2 , further comprising a plurality of spacers that define a distance between the first circuit board and the second circuit board wherein the spacer is made of conductive material. 
     
     
         14 . The isolated switching power supply apparatus according to  claim 13 , wherein the spacers are made of conductive material. 
     
     
         15 . The isolated switching power supply apparatus according to  claim 13 , wherein one of the spacers is connected to the input terminal and another one of the spaces is connected to the output terminal. 
     
     
         16 . The isolated switching power supply apparatus according to  claim 2 , further comprising a heat sink arranged to extract heat from the transformer. 
     
     
         17 . The isolated switching power supply apparatus according to  claim 2 , wherein the primary winding is a coil pattern defined by a single layer of the first circuit board. 
     
     
         18 . The isolated switching power supply apparatus according to  claim 2 , wherein the primary winding is a coil pattern defined by a plurality of layers of the first circuit board. 
     
     
         19 . The isolated switching power supply apparatus according to  claim 2 , wherein the secondary winding is a coil pattern defined by a single layer of the second circuit board. 
     
     
         20 . The isolated switching power supply apparatus according to  claim 2 , wherein the secondary winding is a coil pattern defined by a plurality of layers of the second circuit board. 
     
     
         21 . The isolated switching power supply apparatus according to  claim 2 , wherein each of the primary winding and the secondary winding is a coil arranged around a bobbin or an edgewise coil.